In communication networks, such as telecommunication networks, a call or a service often involves, on the one hand, a control plane or signalling plane and, on the other hand, a user plane or media plane. The control plane or signalling plane is in charge of establishing and managing a connection between two points on the network. The user plane or media plane is in charge of transporting the user data.
In this context, network operators often want to define and enforce a set of rules in the network. A set of rules constitutes policies. A policy framework for managing and enforcing these policies usually includes at least three elements, or functions: a policy repository for storing the policy rules, which may be user-specific, a policy decision element, function or point, and a policy enforcement element, function or point. The purposes of a policy framework include controlling subscriber access to the networks and services.
A policy framework notably addresses the decisions as to whether the subscriber is entitled, or authorized, to enjoy a service, and whether the network can provide the service to the subscriber (and with which quality of service).
Policy and charging control architectures, such as, but not limited to, the architecture described in “3GPP TS 23.203 V10.5.0 (2011-12); Technical Specification Group Services and System Aspects; Policy and charging control architecture (Release 10)” (available on http://www.3gpp.org/ftp/Specs/html-info/23203.htm), integrate the policy and charging control.
In such a policy and charging control (PCC) architecture, the policy and charging rules function (PCRF) is a functional entity in charge of deciding charging, policies and QoS for services of a given user. The PCRF may for instance decide the quality of the connection to be allocated for voice, video, etc, which results, for example, on the establishment of dedicated bearer(s) with guaranteed bit rate (GBR) or non guaranteed bit rate (non GBR). The PCRF may also make decisions about packet forwarding treatment in the radio access network (RAN) by means of determining the quality of service (QoS) class identifier (QCI). The PCRF may also decide, at the packet core control plane, the priority of a bearer to be established over other bearers, for the same or different users, by providing allocation and retention priority (ARP) information.
Based on the above decisions by the PCRF, PCC rules may be generated and installed in a policy and charging enforcement function (PCEF) of the PCC architecture, so that each service is given the appropriate treatment that the service requires. Apart from the PCRF and PCEF, the PCC architecture may also include an application function (AF) interposed between the user and the service to obtain service information to be submitted to the PCRF so that the PCRF can decide the appropriate PCC rules to install in the PCEF.
In operation, where an AF detects service activities for a user (e.g. a voice call), the AF may interact with the PCRF to provide service information and service data flows (SDF). This may lead to the installation of the SDF and the decided QoS information in the PCEF. The PCEF may for instance check if an existing bearer can be used for the SDF or if a new bearer needs be established. If a new bearer is to be established, an ARP value may reflect the importance of this bearer in relation to other bearers at the packet core network and radio access network.
It is desirable to provide methods to improve PCC architectures and implementations, notably by providing a more reliable and efficient PCC architecture without increasing, or at least without excessively increasing, the implementation and architecture complexity and the associated equipment costs.